An optical pick-up is a device for recording or reproducing the information on the optical disc, such as a digital video disk (DVD) or a compact disk (CD). The information recorded on the disc is read by the optical pick-up which projects laser beams on recording pits of the optical disc and receives the reflective laser beam.
Generally, when the optical pick-up reads the information recorded on the optical disc, the optical disc is rotated and the optical pick-up moves along the radial direction of the optical disc so that the optical pick-up can read the entire information on the optical disc. As shown in FIG. 4, a housing 9 supporting the optical pick-up (not shown in FIG. 4) is connected to a connecting unit 7. And, the connecting unit 7 has a tooth-like portion 1. The tooth-like portion 1 engages with the threads of a lead screw 3 to drive and guide the connecting unit 7 to move along the lead screw 3. Therefore, the optical pick-up is moved by the connecting unit 7.
The tooth-like portion 1 must engage with the lead screw 3 so that the optical pick-up will move smoothly. Conventionally, there is an elastic unit 5 disposed between the tooth-like portion 1 and the connecting unit 7. The elastic element 5 provides the tooth-like portion 1 with the elasticity to resist the lead screw 3 so that the tooth-like portion 1 engages tightly with the lead screw 3. However, the foregoing still can't prevent the tooth-like portion 1 and the lead screw 3 from disengaging with each other while experiencing the bigger shake or impact.